[hpsdr] Penelope

n3ick at cox.net n3ick at cox.net
Tue Sep 8 05:35:49 PDT 2009


  Thanks Phil I didn't see any way to check swr with the Penelope just wanted to make sure I didn't miss anything. I'm using a resistive attenuator my target for penelope is 400+mw output but it does fall off on 160 and 10 meters with the attenuator so I may try a carbon pot and see if I can find the magic number. 
  Something else I've noticed with CW using CWX if I hold key down (with two different PC's) I have random transmitted audio dropouts I can hear the dropouts with another receiver and in the monitor audio from PSDR. This is with or without the PA attached. It also does it when sending code with CWX. Unfortunately with my fist it is hard to tell when I use a straight key. 
---- Phil Harman <phil at pharman.org> wrote: 
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > Does the Penelope hardware/software have a way to measure SWR and if so
> > where would you see it? I'm doing some testing with a PA trying to get the
> > match perfect (hi hi) using an attenuator from Penelope feeding the PA
> > with
> > about 2mw. The setup is working just would like to have it more linear
> > across the bands and find easier ways to check when I make changes.
> > Thanks
> >
> 
> Hi Keith,
> 
> Penny does not have any way of measuring SWR.
> 
> Whilst your attenuator method will work fine, if you only need 2mW then
> you may want to consider removing the jumper on the input of the PA chip
> and taking your drive from there.  Alternatively you could replace the
> jumper with a resistive attenuator and use the PA chip. This will improve
> the IMD since the PA would be running at a very low power level.
> 
> I'm sure you already know this but you do not want to reduce the power by
> reducing the drive level from PowerSDR.  You should drive the DAC as hard
> as possible to get the best signal to noise/spur etc ratio.
> 
> In which case your use of an attenuator is fine - just a couple of other
> suggestions.
> 
> 73's Phil...VK6APH
> 
> 
> 
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> 


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